Anyways, I was wondering what kinda effect the system would have if I took 2 speakers off a random stereo and connect them up to the empty ports on the receiver. I am guessing they would be either L&R surrounds or fronts. They are pretty old speakers... so would it be worth it to throw them on for a dvd shindig, or would it take away from the other speakers and make it sound like shat?

I'd advise against it. The voice matching of speakers is crucial for MC audio- especially for the front three. You can get away with a bit of a mismatch in the rears, but for best performance you need the timbre to be similar at least, and identical is best.

I use different speakers on my Denon AVC-A1SRA A/V Amplifier which has independant bass, treble and Level controls, and i find that speaker matching is not a MUST unless your a complete and utter quality freak, i think obviously it would be better having a full matching speaker package, for looks and sound, but i think if you havent then it will still sound extremely nice. If your speakers are of good quality anyway. You should have ports for 2 front, 1 Centre, 2 or 4 Surround, and 1 subwoofer